Computer pointing-input devices used for manipulating a wide range of controls and cursors and other objects presented to the user by windows-type operating systems and application software are well known in the art. U.S. Pat. No. 3,835,464 granted to Xerox Corporation in 1974 disclosed a hand-held computer pointing-input device generally referred to as a "mouse." Many modifications have been made to make such mouse pointing-input devices more functional, easier to use, and less stressful on the hand and arm of the user operating the device; however, the basic function of the mouse device remains substantially the same.
A conventional mouse pointing-input device has a housing which is shaped to be held by a hand of a user. This housing typically has at least one operator-manipulatable control positioned on an upper surface. The mouse pointing-input device is typically moveable over a flat surface within comfortable reach of a keyboard of a computer. Movements of the device over the surface are sensed to provide a pointing-input control signal to the computer. Various methods are known in the art to sense movement of mouse pointing-input devices. Similarly, various methods of transmitting to the computer pointing-input control signals and signals encoding the states of the operator-manipulatable controls on the mouse pointing-input device are well-known in the art.
In the future, windows-based operating systems, and the applications that run under them, will require ever greater levels of computer pointing-input device usage. However, use of conventional mouse pointing-input devices can stress the fingers, hand and arm of the user of a computer system, especially over long periods of use.
Certain conventional mouse pointing-input devices do provide device housings with ergonomically contoured shapes that support the palm of the hand and minimize wrist pronation. However, the arrangement of the operator-manipulatable controls on the surface of such a conventional device usually consists of two or three finger-actuatable controls located at an upper leading edge of the device housing. Examples of such conventional computer pointing-input devices are discussed below.
U.S. Pat. Nos. D349,280 and 5,414,445 each disclose a conventional mouse pointing-input device in which the operator-manipulatable controls consist of two finger-actuatable switches. In operation, these switches are positioned under the operator's index and middle fingers, respectively. A mouse pointing-input device commercially available from Microsoft Corporation of Redmond, Wash. under the tradename Microsoft Mouse Port Mouse also has such a two-switch layout.
A mouse pointing-input device commercially available from Microsoft Corporation under the tradename Microsoft IntelliMouse is similar in design to the Microsoft Mouse Port Mouse but includes a finger-rotatable wheel input device positioned between the two finger-actuatable switches. The wheel input device is typically used to facilitate scrolling, but can also function as a third switch.
A mouse pointing-input device commercially available from Logitech, Inc. of Fremont, California under the tradename Logitech MouseMan uses a three-switch arrangement with the three switches positioned in use under the operator's index, middle and ring fingers, respectively.
The mouse pointing-input devices of the following two paragraphs include thumb-actuatable switches.
U.S. Pat. Nos. 5,530,455 and 5,446,481 each disclose a mouse pointing-input device which incorporates three finger-actuatable switches and a wheel input device similar in operation to the one found on the Microsoft Intellimouse device. In addition, the device also has a thumb-actuatable switch positioned on a side of a body of the device. The thumb-actuatable switch in each of the pointing input devices of the '455 and '481 patents operates in a plane parallel to the surface on which the device is moved in operation. A mouse pointing-input device commercially available from Mouse Systems Corporation of Fremont, Calif. under the trade name Scroll Mouse also has such a thumb-actuatable switch.
A mouse pointing-input device commercially available from Logitech, Inc. of Fremont, Calif. under the trade name Logitech Cordless MouseMan Pro uses a three-switch arrangement similar in function to the Logitech MouseMan device discussed above, but with one switch positioned on a side of a body of the mouse for actuation by the operator's thumb. The remaining two switches of the Logitech Cordless MouseMan Pro device are positioned under the operator's index and middle fingers, respectively. Like the Scroll Mouse device, the thumb-actuatable switch in the Logitech Cordless MouseMan Pro device operates in a plane parallel to the surface on which the device is moved in operation.
While a number of conventional mouse pointing-input devices are shaped to enable the hand of the user to rest comfortably on a body of the device, such conventional devices nonetheless tend to give rise to bio-mechanical stress on the fingers, hand, wrist and arm of a user while the user is actuating the various controls. In general, the actuation of a finger-actuatable switch to generate a "Click" event requires the fingers to apply downward pressure on one or more of the switches. Bio-mechanically, generation of a click event requires the use of the flexor and extensor muscles of the fingers, which reside in the forearm and are attached to the fingers via the flexor tendons, which travel beneath the transverse carpal ligament. Constant repetitive motion can irritate the tendons as well as cause the lubricant surrounding the tendons (called the Tenosynovium) to thicken. As the swelling and thickening continue, pressure is placed upon the Carpal Tunnel, and as a result the Median Nerve is pressed directly against the Transverse Carpal Ligament. Consequently, after extended periods of use of conventional mouse pointing-input devices, it is not unusual for a user to experience a cramping sensation over the dorsum of the hand and of the forearm, and if use is continued, to experience pain.
The use of a conventional mouse pointing-input device such as the devices from Microsoft or the Logitech MouseMan device discussed above often proves to be stressful enough to cause "Carpal Tunnel Syndrome" and/or "Repetitive Stress Syndrome" in a user. The stress giving rise to "Carpal Tunnel Syndrome" and/or "Repetitive Stress Syndrome" is primarily due to the location of the controls which require the use of the fingers, whose tendons travel beneath the Transverse Carpal Ligament, thereby irritating the flexor tendons and placing pressure on the Median Nerve which resides within the Carpal Tunnel. Even conventional mouse pointing-input devices having thumb actuatable switches positioned on the side of the body of the device still have primary switches positioned under the fingers in use, and thus provide the operator with little, if any, relief.
The use of alternative devices such as touch pads, track balls, joy sticks, and other non-mouse type devices ordinarily tends to lead to a decrease in operator productivity, particularly among persons accustomed to using mouse pointing-input devices. Such productivity loss is ordinarily not due to pain or fatigue, but simply to the cumbersome design and usage of the non-mouse type devices.
U.S. Pat. No. 4,862,165 to Samuel Gart ("the Gart '165 patent") discloses a mouse pointing-input device shaped reportedly to reduce hand fatigue. The mouse device of the patent includes two depressible switches respectively for the forefinger and thumb. According to FIGS. 1 and 4 of the Gart '165 patent, the depressible switch for the thumb is located on a side of the mouse device. While the shape of a mouse pointing-input device is generally important in any design, the shape has virtually no impact on two of the most troublesome problems arising from the use of such devices: "Carpal Tunnel Syndrome" and "Repetitive Stress Syndrome." The presence of a depressible switch for the forefinger of the mouse device of the Gart '165 patent results in the users of the device being at risk for developing "Carpal Tunnel Syndrome" and "Repetitive Stress Syndrome." Moreover, with the mouse device of the Gart '165 patent (as with the Mouse Systems Scroll Mouse mouse device and the Logitech Cordless MouseMan Pro mouse device), the location of the depressive switch for the thumb on a side of the device means that pressing the switch would put lateral pressure on the mouse body, thus reducing stability and accuracy of the device, and, as a result, reducing productivity of the user.